Steam generator and water heater



April 22, 1930. T. cLARKsoN STEAM GENERATOR AND WATER HEATER Filed May 16, 1928 Patented Apr. 22, 1930- PATENT OFFICE THOMAS CLARKSON, OF LONDON, ENGLAND STEAM GENERATOR AND WATER HEATER Application tiled Hay 16, 1928, Serial No. 278,111, and in Great Britain Hay 80, 1927.

This invention relates to steam generators or water heaters of the type comprising two concentrically arranged substantially cylindrical members of different diameters each closed at its lower end while the uper ends are connected together so that a steam and water space is formed between the two members of which the inner one carries a series of thimbles projecting radially into a central gas space.v

Where heat is supplied to a generator or water heater of this type by means of a ame as from a burner directed downwardly into the central gas space, the excessive heat which is then directed against the centre portion of the lower end of the inner member of the generator tends to cause damageto this part. This is due to the fact that it has been customary hitherto to form as flatly rounded or with a curvature of large radius the closed I per end of the the air supply thereto so as to obviate the risk of damage to the lower part of the generator while providing means for cooling the upper part of the generator casing.

According to the present invention the closed lower end of the inner member of the steam generator or water heater i's formed substantially conical the angle of the apex of the cone being conveniently not more than 120. A baiile member is provided in the water space between the concentric inner and outer generator members this batlie member being formed approximately cylindrical as to its upperpart with an inwardly directed and substantially conical base having a central opening therein. This baliie member is disposed so as to lie between and be spaced apart from the inner and outer steam generator members so that the water space, not only in the vertical annular portion of the generator, but also at the bottom thereof, is divided by the baie member in such a manner .thatl circulation of the water will tend to be induced downwards outside the baille and towards the centre of the bottom of the generator and thence upwards inside the baile over the conical lower end of the inner generator member and the upper art of this member which carries the thimb es. By this means such a circulation of water is caused to take place over the lower end of the inner generator member as' will obviate the risk of the centre portion of this lower end being damaged by the heat impinging thereon.

The diameter of the cylindrical portion of the baille is appreciably less than the internal diameter of the outer shell or member of the generator but substantially greater than the outer diameter of the inner generator member. The lower portion of the baiil'e is given a conical formation substantially conorming to that of the lower end of the inner generator member. The openin in the centre of the conical lower end of t e baiile is of suitable dimensions and the spacing between this part and the conical lower end of the inner generator member is such as to allow of free iiow and the desired upward scouring circulation of the water over the conical surface of the inner end ofthe generator and between this part and the baie.

Refractory material such as rebrick preferably in a broken state may be disposed in the centre of the conical lower end of the inner generator member so that the heat from the downwardly directed ame will impinge on to this material.

The burner is preferably arranged so as to direct the flame into the interior of the inner generator member through a tubular inlet passage which is so dis osed in the upper part of the generator that 1t is surrounded b3' an annular space which may be regarde as ormin a chamber through which the hot gases a er flowin over the generator thim- `bles, pass upwar s to a laterally arranged gas outlet at the upper end of the enerator casing. This tubular gas inlet or ame passage is preferably provided in its upper part with a conical perforated member immedlate- 1y below which is arranged a rebrick or like 10 lining. The liquid fuel burner is carried by a plate mounted at the upper end of the generator so that the ame is directed downwards through the conical perforated member and the irebrick lined portion of the tubular flame passage into the central gas space of the generator, the tubular ame passage preferabl being extended downwards below the fire rick lined portion into the space between the thimble tubes.

The invention may be carried into practice in 'various ways but one construction according to this invention is illustrated by way of example inthe accompanying dra-wlngs, 1n which Figure 1 is a sectional elevation, and Figure 2 is a plan. e lIn the construction illustrated the generator or water heater comprises two concentric tubular generator members A and B of different diameters each closed at its lower end and open at its upper end, the upper ends being connected together for example by a separate annular member C so as to enclose between the generator members a space A1 for water or water and steam. The lower closed end A2 of the outer generator member A, which in the construction shown is formed separately from and secured to the tubular wall of this member but may if desired be formed integral with such tubular wall, has a substantially spherical surface. The lower closed end B1 of the inner generator member B which may also be formed either integral with or, as shown, separately from the tubular wall of such-member, is, on the other hand, formed substantially conical, the angle at the apex of the cone being as shown not more than 120. The apex of the cone is conveniently rounded olf as shown at B2 and may be provided internally with'a lling of refractory material B3 such as frebrick, preferably in a broken state. l

A series of closed-ended water tubes D extend radially inwards from theA wall of the inner generator member B, a portion B* of the tubular wall of this member towards its upper end being unprovided with thimble tubes and somewhat reduced in diameter.

lArranged in the annular water space A1 between the inner and outer generator members and having` a diameter less than the in? ternal diameter of the outer generator member, but greater than `the external diameter of the inner generator member, is a baiiie member E E1, this baille member being lformed approximately cylindrical as to its upper part E with an inwardly directed and substantially conical base E1 having a central opening E2 therein. The baiile member E E1 is conveniently supported on studs E3 from the outer generator member A and is disposed as shown so as to lie between and be spaced apart from the inner and outer generator members so that the water space,

not only in the vertical annular portion of the generator but also at the bottom thereof, is divided by the battle member E E1 in such a manner that circulation of the water will tend to be induced downwards outside the balie and towards the centre of the bottom A2 of the generator and thence through the hole E2 and upwards over the conical lower end B1 of the inner generator member and the upper part of this member which carries the thimble tubes D. Further, a deflecting member B5 may be provided on the lower end A2 of the outer generator member A to assist the flow of water into the opening E2 in the baffle E E1. Secured to the annular member C connecting the upper ends of the inner and outer generator members is a structure F hereinafter termed a burner case. This case F is so formed as to close in the upper portion of the gas space G of the generator and to form in effect an annular chamber G1 constituting an extension of such gas space into which the gases flow after passing out of the inner generator member proper and before flowing to an outlet pipe G3 leading from the annular chamber G1.

The outlet G3 conveniently leads laterally from the chamber G1 and the burner case F conveniently comprises in addition to the chamber G an outer chamber H surrounding the chamber G1 except where the outlet Gs n leads therefrom and also extending over the top of the chamber G1, the chamber H communicating with the atmosphere through a suitable passage H1 whichmay be provided with a fan or blower.

The upper wall of the chamber H1 is constituted partially or wholly by a plate J in the centre of which is carried a fuel sprayer K arranged substantially coaxially with the generator and preferably of the type employing an atomizing blast of air or steam. The burningv gases and products of combustion from the sprayer are directed through a. flame tube L L1 into the interior of the inner generator member B, the upper portion L of the ame tube constituting the 1nne-r wall of each of the annular chambers G and G1. The upper portion L of the flame tube 1s of somewhat larger diameter than the ,as shown and being held in place by the tubular member M. The external diameter of the refractory lining M2 is somewhat less than the internal diameter of the surrourl'ding portion of the flame tube so that a small air space'M3 surrounds the refractory lining,-

this lining bein provided with ribs or serrations M at its ower end as shown so as to prmit air to pass laterally from the s ace into the lower` portion L1 of the ame tu e.

It will be seen that with the construction illustrated, since the perforated cylinder M is of less diameter than the upper portion L of the flame tube, air can -llow from the interior of the casing M into the annular space between the cylinder M and the llame tube L. This air can flow downwards through the s ace M3 surrounding the refractory lining 2 and thence radially into the lower end L1 of the flame tube whereby the upper portion L of the flame tube is insulated by a jacket of cool air from the intense heat of the refractory lining M1. The extreme lower end of the flame tube is conveniently tapered somewhat as indicated at L1.

The operation of the burner ,described above is as follows. The air for combustion enters through the inlet passage H1 in the chamber H either directly from the atmoshere or under pressure from a blower or an and in so doing will pass over the outer wall of the chamber G1 and thus will become heated since the hot gases from the enerator pass through the chamber G1 on their way to the gas outlet G. Some of this air will enter the perforated conical member M1 at its upper end adjacent to the sprayer and will mingle with the fuel delivered thereby and serve for the combustion of such fuel sab while the remaining air flows into the space between this conical member and the perforated cylinder M and thence passes partly throu h the perforations in the conical member B and partly through the perforations in the cylindrical member M. 'e air passing through the perforations in the conical member M1 assists in the combustion of the fuel delivered by the sprayer K while that passing throughthe perforations in the cylindrical member M passes downwards through the space between this member and the llame tube L into the space lMa between the flame tube and the refractory lining M2 whence it passes out through the radial openings into the lower end L1 of the flame tube.

The hot gases from the burner flow downwards through the llame tube into the lower en d of the inner generator member B and after flowing upwards around and over the thimble tubes D will pass around the upper ortion L of the flame tube into the chamber g1 whence they pass to the gas outlet G.

The heat from the gases delivered by the burner is transmitted through the thimble tubes D and the wall of the inner generator member B to the water and will cause the water within the baille E to flow upwards. The upward flow thus caused within the cylindrical portion of the baille E, assisted y the conicity of the closed lower end B1 of the inner generator member B, will tend to produce a rapid combined radial and upward flow of water between the conical lower ortion E1 of the baille E and the conical end 1 o f th'e inner generator member B thus tending to maintain this end cooled and to revent the formation of stationary steam ubbles thereon.

"The generator is conveniently provided with an inlet ipe N for feed water and a perforated col ecting pi e O for steam.

o It is to lbe understoo tional details may be varied within wide limits without departing from this invention according to the purpose for which the generator or water heater is intended and the type of burner which is to be employed. Further, although the invention has been described with particular reference to nerators or water heaters employin liquid or gaseous fuel burners, it may alsoe applied to generators or water heaters in which the hot gases are derived from some other source wherein the temperature of these gases is such as to tend to cause over-heating of the lower closed end of the inner generator member.

What I claim as my invention and desire to secure by Letters Patent is 1. A water heater includin in combination a cylindrical outer shell 'sposed vertically and having the lower end thereof closed, a tubular inner shell whose external diameter is less than the internal diameter of the outer shell and having a conical closureiat its lower end, the two shells being disposed concentrically with a steam and water space between their sides and lower ends, an annular member connecting the upper ends of these shells and closin in the steam and water space, a series o? thimble tubes projecting radially inwards from the wall of the inner shell into a central heating space, a downwardly directed burner mounted opposite to the open end of the inner shell and delivering hot gases into this heating space, a sheet metal baille member comprising a tubular main part and va conical end portion with a central opening therein this baille member being disposed in the steam and water space where it lies intermediate between the adjacent external and internal side and end surfaces ofthe inner and outer shells, the baille tending to cause water to circulate downwardly between the baille and the outer shell through the opening in the lower end of the baile member and upwards between this member and the inner shell.

2. A water heater includin in combination a cylindrical outer shell isposed vertically and having the lower end thereof closed, a tubular inner shell whose external diameter is less than the internal diameter of the outer shell and having a conical closure at its lower end the angle at the apex of which is not Amore than 120, the two shells being disposed that the construcconcentrically with a steam and water space between their sides and lower ends, an annular member connecting the upper ends of these shells and closing in the steam and water space, a series of thimble tubes projecting radially inwards from the wall of the inner shell into a central heating space, a downwardly directed burner mounted opposite to the open end of the inner shell and delivering hot gases into this heating space, a sheet metal baie member comprising a tubular main part and a conical end portion with a central opening therein, this baille member being disposed in the steam and water space vwhere it lies intermediate between the adjacent external and internal side and end surfaces of the inner and outer shells, the baie tending to cause water to circulate downwardly between the baiile and the outer shell, through the opening in the lower end of the baffle member and upwards between this member and the inner shell.

3. A water heater including in combination a cylindrical outer shell disposed vertically and having the lower end thereof closed, a tubular inner shell whose external diameter is less than'the internal diameter of the outer shell and having a conical closure at its lower end the angle at the apex of which is not more than 120, the two shells being disposed concentrically with a steam and water space between their sides and lower ends, an annular member connecting the upper ends of these two shells and closing in the steam and water space, a series of thimble tubes projecting radially inwards from the wall of the inner shell into the central heating space and a downwardly directed burner mounted opposite to the open end of the inner shell and delivering hot gases into this heating space.

4. A water heater including in combination a cylindrical outer shell disposed vertically and having the lower end thereof closed, a tubular inner shell whose external diameter is less than the internal diameter of the outer shell and having a conical closure at its lower end, the two shells being disposed concentrically with a steam and water space between their sides and lower ends, an annular member connecting the upper ends of these shells and closing in the steam and water space, a series of thimble tubes projecting radially inwards from the wall of the inner shell into a central heating space, a downwardly directed burner mounted opposite to the open end of the inner shell and delivering hot gases into this heatin space, a flame tube into the upper end of w ich the hot ases from the burner pass, this flame tube eing disposed concentrically with the inner shell between the closed inner ends of the thimble tubes and of such length that the hot gases after iowing through the flame tube pass from the lower end thereof into the heating space adj acentto its lower end and only come in contact withthe thimble tubes during their upward motion through the space surrounding the flame tube as they pass towards a gas outlet at the upper end of this s ace, a tapered and perforated tubular mem er in the upper portion of the flame tube arranged with its smaller end adjacent to the burner, a `refractory lining for the portion of the flame tube immediately below this perforated member, means for supplying air to the upper end of the iame tube and the space surrounding the perforated tubular member, means for permitting the escape of hot gases from the space surrounding the upper end of the flame tube, a sheet metal baiiie member comprising a.` tubular main part and a conical end portion with a central opening therein, this baie member being disposed in the steam and water space where it lies intermediate between the adjacent external and internal side and end surfaces of the inner and outer shells, the baille tending to cause water to circulate downwardly between the-baiile and the outer shell, through the opening in the lower end of the baiiie member and upwards between this member and the inner shell.

5. In a water heater, the combination with a substantially vertical container for water provided with a heating space interiorly thereof, of a burner arranged to deliver hot gases downwardly into the said heating space, a flame tube into the upper end of which the hot ases from the burner pass, this flame tube eing disposed within the heating space and of such length that the hot gases after owing through the ame tube pass from the lower en d thereof into the heatmg space adjacent to its lower end and only come in contact with the container walls during their upward motion through the space surrounding the ame tube, an annular chamber surrounding the upper end of the flame tube and into which the hot gases iiow before issuing from the heating space, and an air inlet passage surrounding this annular chamber and serving to deliver air to the upper end of the flame tube.

6. In a water heater, the combination with a substantially vertical container for water provided with a heating space interiorly thereof, of a burner arranged to deliver hot gases downwardly into the said .heating space, a llame tube into the upper end of which the hot gases from the burner pass, this ame tube being disposed within the heating s ace and of such length that the hot gases a er flowing through the iiame tube pass from the lower end thereof into the heating space adjacent to its lower end and only come in contact with the container walls during their upward motion through the space surroundin the flame tube, a tapered and perforated tubular member in the upper portion of the ame tube arranged with its smaller end adjacent to the burner, a refractory lining for the portion of the fiame tube immediately below this perforated member, an annular chamber into which the hot gases pass after flowing u wards through the space surrounding t e y flame tube, an outlet from this chamber, and an air inlet passage surrounding this annular chamber and serving to deliver air to the upper end of the iiame tube and the space Surrounding the tubular performated member.

In testimony whereof I have signed my name to this specification.

THOMAS CLARKSON. 

